1. Field of the Invention
The present invention is in the general field of poultry farming and relates to the feeding of fowl, including layers and broiler breeders. In a particular aspect, it relates to a method of feeding female birds with a feed formulation which enhances, for example, egg production, and/or egg shell quality. This invention also relates to the eggs with improved egg shells obtained from birds fed a diet of this invention. Poultry diets of this invention are typically diets which include an egg shell characteristic-enhancing amount of a zeolite such as zeolite A, and reduced chloride levels, e.g. levels below that recommended previously by the National Research Council. This invention also relates to improved poultry farming. Thus, it relates to methods which provide improved egg or broiler production. These methods comprise obtaining an increase in yield of marketable or settable eggs from laying hens. The increase is provided by feeding hens a diet of this invention.
2. Description of Related Art
In previously issued patents, we disclosed that zeolite A enhances egg shell quality, U.S. Pat. No. 4,556,564; improves feed utilization efficiency, U.S. Pat. No. 4,610,882; and improves liveability, U.S. Pat. No. 4,610,883. The disclosures in those patents are incorporated by reference herein as if fully set forth. Other related art is mentioned in the patents.
An article by C. Y. Chung et al from Nongsa Sihom Youngu Pogo 1978, 20 (Livestock) pp. 77-83 discusses the effects of cation exchange capacity and particle size of zeolites on the growth, feed efficiency and feed materials utilizability of broilers or broiling size chickens. Supplementing the feed of the broilers with naturally occurring zeolites, such as clinoptilolite, some increase in body weight gain was determined. Chung et al also reported that earlier results at the Livestock Experiment Station (1974, 1975, 1976--Suweon, Korea) showed that no significant difference was observed when 1.5, 3, and 4.5 percent zeolite was added to chicken layer diets.
U.S. Pat. No. 3,836,676 issued to Chukei Komakine in 1974 discloses the use of zeolites and ferrous sulfate crystals in an odorless chicken feed comprising such crystals and chicken droppings. The results were said to be no less than those in the case where chickens were raised with ordinary feed.
Experiments have been in progress in Japan since 1965 on the use of natural zeolite minerals as dietary supplements for poultry, swine and cattle. Significant increases in body weight per unit of feed consumed and in the general health of the animals was reported (Minato, Hideo, Koatsugasu 5:536, 1968). Reductions in malodor were also noted.
Using clinoptilolite and mordenite from northern Japan, Onagi, T. (Rept. Yamagata Stock Raising Inst. 7, 1966) found that Leghorn chickens required less food and water and gained as much weight in a two-week trial as birds receiving a control diet. No adverse effects on health or mortality were noted. The foregoing Japanese experiments were reported by F. A. Mumpton and P. H. Fishman in the Journal of Animal Science, Vol. 45, No. 5 (1977) pp. 1188-1203.
Canadian Pat. No. 939,186 issued to White et al in 1974 discloses the use of zeolites having exchangeable cations as a feed component in the feeding of urea or biuret non-protein (NPR) compounds to ruminants, such as cattle, sheep and goats. Natural and synthetic as well as crystalline and non-crystalline zeolites are disclosed. Zeolites tested included natural zeolites, chabazite and clinoptilolite and synthetic zeolites X, Y, F, J, M, Z, and A. Zeolite F was by far the most outstanding and zeolite A was substantially ineffective.
In a study at the University of Georgia, both broilers and layers were fed small amounts (about 2%) of clinoptilolite, a naturally occurring zeolite from Tilden, Tex. The egg shells from the hens receiving zeolite were slightly more flexible as measured by deformation, slightly less strong as measured by Instron breaking strength, and had a slightly lower specific gravity. The differences in egg shell quality were very small. This type of zeolite was ineffective in producing a stronger egg shell. An article written by Larry Vest and John Shutze entitled "The Influence of Feeding Zeolites to Poultry Under Field Conditions" summarizing the studies was presented at Zeo-Agriculture +82.
A study by H. S. Nakone of feeding White Leghorn layers clinoptilolite, reported in 1981 Poultry Science 60:944-949, disclosed no significant differences in egg shell strength between hens receiving the zeolite and hens not receiving the zeolite.